Renewable fuse



May 27 1941 H. scHElNBElM 2,243,287

RENENABLE FUSE Filed 001;. 25, 1938 INVENTOR.

HYM N SCHEINBHM/ www mgm/f ATTORNEY.

Patented May 27, 1941 UNITED STATES PATENT OFFICE RENEWABLE FUSE HymanScheinbeim, New York, N. Y.

Application October 25, 1938, Serial No. 236,812

(Cl. 20D-131) 11 Claims.

This invention relates to renewable fuses for breaking an electricalcircuit when the current reaches a predetermined value.

The present type of renewable fuse commercially used comprises a copperalloy cap having machined threads mounted on the two ends of a hardfibre casing similarly threaded. Since the two caps are inserted into apair of metallic clips forming a fuse holder, the caps should be made ofpure copper for maximum conductivity. Pure copper, however, is diflicultto machine because the copper drags Accordingly, a primary object `of myinvention consists in providing ferrules or caps of pure copper that may\be used Without machining.

Fuses visibily indicating the actual capacity of the fuse link are notused commercially, although shown in the prior art. This results fromimproperly positioning the visible portion of the link when assembled.

A further object, therefore, is to provide a fuse in which the capacityof the fuse link will be indicated visibly and from the front positionwhen the fuse is installed in the holder and which renders unnecessarythe use of a. fuse link that is longer than the cartridge.

Other objects are to provide an inexpensive, renewable fuse of thecartridge or vknife-edge type, capable of being easily and quicklyrenewed with maximum safety, having maximum area of contact with thefuse supporting socket, with blocking means for preventing the vaporizedmetal of the fuse link from being ejected externally creating rehazards, and having means for preventing accidentally or otherwise, theinsertion of more than one fuse link or an oversized link in the fusechamber.

I accomplish these and other objects and obtain my new results, as willbe apparent from the device described in the following description,particularly pointed out in the attached claims, and illustrated in theaccompanying drawing, in which:

Fig. 1 is a plan view of my fuse.

Fig. 2 is an end view of the same.

Fig. 3 is a longitudinal sectional view.

Fig. 4 is a longitudinal sectional view of one end illustrating amodified blocking means for increasing the contacting end of myferrules.

Fig. 5 is a plan view of my knife edge fuse.

Fig. 6 is an end view -of the same.

Fig. 7 is a longitudinal sectional view.

Fig. 8 is a sectional plan view of one end illustrating the knife edgesupported therein.

In the drawing, reference numerals I8 and II designate the body of mycartridge which may be formed into two sections, each made of suitableelectrically insulating and nre-resisting material. Each sectioncontains a cavity I2 and I3 through which the fuse link I4 is suspended.

Ferrules I5 and I6 made of pure copper are slipped over the ends ofsections I0 and II. The ferrules are provided with a suitableindentation Il and I 8, preferably rectangular, forming a seat for thefuse link I4 and enabling bolts I9 and 20 to be threaded therein, thusavoiding any projection beyond the cylindrical surface of the ferrules.

As shown in Fig. 3, each section, like section I0 illustrated, isprovided with a passage-way 2| and 22 through which the fuse link I4extends. An angular or V-shaped clip 23 is inserted at each end havinglegs 24 and 25, the latter tting into ridge 26 of each end of sectionsI0 and II, completely blocking the passage-way 2l and 22, preventing themetallic vapors from escaping. The leg 24 of each clip 23 is aperturedas at 2'I to permit bolts I9 and 20 to enter.

The legs 24 and -25 fit snugly into ridges 26, permitting only a xedthickness of fuse link to be inserted under the legs 24 and 25. Agreater thickness of fuse link, whether inserted accidentally orotherwise, will prevent the angular clips from being properly seated,blocking the insertion of the bolts.

The fuse link I4 extends beyond the clips 23, leaving exposed a smallvisible area upon which the fuse amperage is stamped. The indented endsIl and I8, of the ferrule I5 and I6, are apertured for entrance of thebolts I9 and 20, and a small recess 30 and 3| is moulded into thesections to permit nuts 28 and 29 to be inserted therein for tighteningthe clips, link and ferrule together into a unitary assembly. The recessalso serves to hold the bolt and nut and keep the ferrule assembly fromslipping off the ends of the section.

A passage-way 32 and 33 extends transversely through the ends of thesections I0 and II, axially aligned with the bolts to permit bolts ofvarying lengths to be accommodated.

The bottom surface of the ferrules are depressed as at 34 and 35 toassist in locking the ferrules to the sections.

In positioning the two identical and interchangeable sections Ill and IItogether, slots 36 and 3l may be moulded therein each section, intowhich suitable cement may be placed for securing the two sectionstogether, and to avoid escape of the metallic vapors from the fuse link.

An additional leg extension 35 of the clip 23A thus forming a U-shape isshown in Fig. 4, in the event the fuse should be rotated in thesupporting socket and an electrical contacting and supporting member isdesired, extending transversely across the rectangular indentation ofthe ferrule.

ln Figs. 5, 6, 7 and 8 various Views of the same fuse are shown butprovided with the familiar knife edge type of engaging means. This isidentical in every way with the former type, except that the nuts 28 and29 are replaced by knife blade members di] and tI. The moulded sectionsH3A and IIB are changed to accommodate the knife blade members, recesses3!! and 3l of the device illustrated in Fig. 3 being enlarged as shownin Figs. 7 and 8, to accommodate knife blades il@ and Iii provided withv cuts, 42, into which moulded Vs, 53, extend. The apertures 4d and 45of the knife blades il and QI are threaded for engagement with bolts ISAand 20A.

The devices illustrated employ ferrules which are manufactured by takingtubular sections of pure copper and providing them with the rectangularindentations above referred to, or by forming the tubular lengths withcontinuous depressed sections. rThese are cut off into the desirablelengths, provided with bolt apertures and two bolts hold the entireassembly into position. The devices possess as much continuous surfacesin engagement with the supporting sockets as the former types to insureminimum electrical resistance. A possible variation of the tubular cutoisections would be to use a at copper stamping of the saine metal, withthe ends adjacent dep essions 34 and 35. Such a variation would give theend ferrules a compressible feature not obtainable by the tubularcut-ofi sections, advantageously useful for holding the ferrules to thebody member and for general economy.

The sections a e interchangeable as well as the two ferrules insuring asmaller investment in tools and a simpler and cheaper assembly charge.The fuse links can be easily removed and reinstated with just two boitebeing Unthreaded, and

are provided with visible ampere ratings on their ends.l

While the body is shown illustrated in two identical sections, it isobvious that one section may be employed having substantially the samefuse chamber and fuse link supporting shoulders.

I have thus described my invention, but I desire it understood that itis not coni-ined to the particular forms, shapes or uses shown anddescribed,

the same being merely illustrative, and that the invention may becarried out in other ways without departing from the spirit of myinvention, and, therefore, I claim broadly the right to ernploy allequivalent instrumentalities coming within the scope of the appendedclaims, and by means of which, objects of my invention are attained andnew results accomplished, as it is obvious that the particularembodiments herein shown and described are only some of the many thatcan be employed to attain these objects and accomplish these results.

What I claim and desire to secure by Letters Patent, is as follows:

1. A renewable fuse having a fuse link; a body section provided with afuse chamber; two cylindrical and tubular end ferrules having indentedsections on their cylindrical surfaces for engaging the ends of the fuselink; and means for electrically and mechanically connecting the fuselink to the f-errules.

Til

2. A renewable fuse having a fuse link; a body section provided with afuse chamber; two cylindrical and tubular end ferrules having indentedsections on their cylindrical surfaces for engaging the ends of the fuselink; and bolts for electrically connecting the ends of the fuse linksto the ferrules.

3. A renewable fuse having a fuse link; a body section provided with afuse chamber; two cylindrical and tubular end ferrules having indentedsections cn their cylindrical surfaces for engaging the ends of the fuselink; the ends of the body shaped to receive the tubular end ferruleswith the indented sections.

4. A renewable fuse having a fuse link; a body section provided with afuse chamber and passageways leading therefrom to each end; twocylindrical and tubular end ferrules having indented sections on theircylindrical surfaces for engaging the ends of the fuse link; bolts forelectrically connecting the ends of the fuse links to the ferrules; andV shaped metallic clips having an aperture for said bolts, forcompressing said fuse links to said end ferrules and for blocking thepassageways from the ends of the body section to the passageway.

5. A renewable fuse having a fuse link; a body section provided with afuse chamber; two cylindrical and tubular end ferrules having indentedsections on their cylindrical surfaces for engaging the ends of the fuselink; means for electrically and mechanically connecting the fuse linkto the ferrules; and means for limiting the thickness of the fuse linkinsertable into the fuse chamber.

6. A renewable fuse having a fuse link; a body section provided with afuse chamber; two cylindrical and tubular end ferrules having indentedsections on their cylindrical surfaces for engaging the ends of the fuselink; and bolts for electrically connecting the ends of the fuse linksto the ferrules; said fuse links having their fuse capacity indicatedthereon adjacent the 10ngitudinal end of the fuse link and visibletherefrom.

'7. A renewable fuse having a fuse link; a body formed of twosymmetrical sections providing a central fuse chamber when assembledtogether; two cylindrical and tubular end ferrules holding said bodysections together, having indented sections on their cylindricalsurfaces for engaging the ends of the fus-e link; and means forelectrically and mechanically connecting the fuse link to the ferrules.

8. A renewable fuse having a fuse link; a body formed of two symmetricalsections providing a central fuse chamber when assembled together, eachsymmetrical section provided with longitudinal slots for entrance of acement for sealing the two body sections together along the longitudinalline of junction; two cylindrical and tubular end ferrules havingindented sections on their cylindrical surfaces for engaging the ends ofthe fuse link; and means for electrically and mechanically connectingthe fuse link to the ferrules.

9. A renewable fuse having a fuse link; a body section provided with afuse chamber and passageways leading therefrom to each end; twocylindrical and tubular end ferrules having indented sections on theircylindrical surfaces for engaging the ends of the fuse link; bolts forelectrically connecting the ends of the fuse links to the ferrules and Ushaped metallic clips having an aperture for said bolts, for compressing11. A renewable fuse having a fuse link; a body section provided with afuse chamber; two cylindrical and tubular end ferrules having indentedsections on their cylindrical surfaces for engaging the ends of the fuselink; a, pair of extending knife-like blades extending from the twoopposite ends of said fuse having engaging means for interlocking withthe body of said fuse; and means for electrically and mechanically con-10 necting the fuse link to the ferrules.

HYMAN SCHEINBEIM.

